Answer this question truthfully
### Question: What causes Neuroendocrine tumors?
### Response: In the normal pancreas, cells called islet cells produce hormones that regulate a variety of bodily functions, such as blood sugar level and the production of stomach acid.
Tumors that arise from islet cells of the pancreas can also produce a variety of hormones, though some do not.
Although islet cells produce many different hormones, most tumors release only one hormone that leads to specific symptoms. Pancreatic islet cell tumors can be noncancerous (benign) or cancerous (malignant).
Islet cell tumors include:
Gastrinomas (Zollinger-Ellison syndrome) Glucagonomas Insulinomas